1. Field of the Invention
The present invention relates to a method and a system for interpolation-processing delay time data which has been supplied to delay circuits, incorporated in an ultrasonic diagnosis apparatus, for transmitting and receiving ultrasonic beams.
2. Description of the Related Art
An ultrasonic diagnosis apparatus has a delay circuit incorporated in the signal-transmitting system or the signal-receiving system, or both. The signals input to the delay circuit are delayed, and are output to transmitter or receiver, or both. These delay signals are used to operate transducers incorporated in the probe. The probe transmits and receives an ultrasonic beam which is deflected in a desired direction and focused on a desired position.
In order to obtain a tomographic image of a subject by means of such an ultrasonic diagnosis apparatus, various delay time data times required for transmitting and receiving ultrasonic beam are supplied to a delay circuit in accordance with several factors (hereinafter called "delay time-varying factors"), such as the positions of the transducers which must be used, the number of rasters required to form the tomographic image, and the number of focal points.
Hitherto, the delay time required for transmitting and receiving ultrasonic beams has been calculated by a computer, the resultant data being stored in a RAM and read out therefrom, when required, and transferred to the control circuit of the transmitting and receiving system of the ultrasonic diagnosis apparatus. The more delay time-varying factors there are, the greater the amount of delay time data which must be stored in the memory, and hence the larger the capacity the memory must have. When the amount of delay time data required increases in accordance with delay time-varying factors, a number of problems arise, in view of the time needed for transfer of the delay time data, in using the transducers at different times.
Therefore there is a demand for an apparatus which can use all transducers incorporated in a probe, by using a relatively small delay time data even if there are many delay time-varying factors.